In an increasingly heterogeneous network environment, it is often necessary to map circuit emulated services (CES), such as T1/E1 private line services, to a cell or packet infrastructure, such as an Asynchronous Transfer Mode (ATM) or Internet Protocol (IP) network environment, respectively. A number of techniques have been proposed or suggested for mapping CES to cells or packets. Typically, independent hardware is employed to map CES to a cell structure (such as associated with an ATM network) and to map CES to a packet structure (such as associated with an IP network). While such independent circuits effectively map CES to cells and packets, this independent approach results in increased power dissipation, additional logic design and a larger surface area
Constant Bit Rate (CBR) services have been employed to emulate leased lines. Since ATM networks generally employ cells and IP networks generally employ packets, as opposed to a circuit-based transmission technology, circuit characteristics must be emulated in these networks in order to support CBR traffic. The need for circuit emulation within ATM and/or IP networks reflects an increasing demand for carrying CBR traffic over such networks. “Circuit Emulation Service Interoperability Specification, Version 2.0,” ATM Forum Specification, atm-vtoa-0078 (CES 2.0) (January, 1997), describes the use of an ATM Adaptation Layer 1 (AAL1) format for circuit emulation over ATM. Y Stein et al., “TDM Over IP,” Internet Engineering Task Force (IETF), draft-ietf-pwe3-tdmoip-03.txt (Feb. 27, 2005), describe a technique for transmitting N ATM AAL1 payloads per packet over an IP network to achieve circuit emulation over IP networks.
A need exists for methods and apparatus for simultaneous support of Circuit Emulated Services over a cell infrastructure or over a packet infrastructure. A further need exists for methods and apparatus for simultaneous support of Circuit Emulated Services using a mapping/demapping function between ATM cells and packets. Yet another need exists for methods and apparatus for simultaneous support of Circuit Emulated Services using shared hardware for one or more of cell/packet translation, dejitter buffering and clock recovery. In addition, a need exists for multiple services over a packet switched network with a common management approach